Pat Dealy played five years in the majors, appearing in three different leagues. He was primarily a catcher (85 games), playing also at shortstop (25 games), third base (14 games), outfield (11 games) and first base (1 game). He also umpired two National League
games in 1886.

He was never the starting catcher in the majors. In the year when he got his most at-bats, 1887, the starting catcher was Connie Mack, who was in 76 games at the position while Dealy was in 28. Dealy was also in 23 games at shortstop that season and several at third base and in the outfield.

Dealy is said to have allowed 10 passed balls in a game on May 3, 1886, which is odd given that he appeared in 14 games at catcher that season and allowed a total of 20 passed balls, which means that he had a total of 10 in the other 13 games. It was apparently typical to allow one passed ball per game - Dealy allowed 24 during 28 games at catcher in 1887 while Connie Mack allowed 76 passed balls during 76 games at catcher in 1887.